CONVECTIVE FORECAST
VALID 06Z TUE 27/05 - 06Z WED 28/05 2003
ISSUED: 26/05 21:01Z
FORECASTER: DAHL

GENERAL THUNDERSTORMS ARE FORECAST ACROSS EASTERN AND CENTRAL EUROPE

SYNOPSIS

UPPER WERSTERLIES EXTENDING ACROSS NORTHERN PARTS OF EUROPE ... WHILE TWO CLOSED UPPER LOWS ARE PRESENT OVER THE SW MEDITERRANEAN AND THE SE BALKAN STATES/TURKEY RESPECTIVELY. SYNOPTICALLY QUIESCENT CONDITIONS WILL PREVAIL ACROSS CENTRAL EUROPE WITH SUBTLE UPPER RIDGING EXPECTED PER LATEST MODEL DATA. AT LOW LEVELS ... SFC LOWS ASSOCIATED WITH THE UPPER LOWS ARE EXPECTED TO CONTINUE TO FILL OVER THE PERIOD. HIGH PRESSURE OVER W EUROPE/E ATLANTIC IS PROGGED TO SPREAD NORTH IN RESPONSE TO THE MID/UPPER RIDGING.

DISCUSSION

...CENTRAL AND EASTERN EUROPE...
AIRMASS OVER E AND SE PORTIONS OF EUROPE IS WEAKLY CAPPED ... WHILE MLCAPES ON THE ORDER OF 500 TO 1500 J/KG ARE COMMON OVER THIS REGION. LATEST OBS SUGGEST THAT LOW-LEVEL MOISTURE IS RATHER HIGH /SFC DEWPOINTS AROUND 15 TO 18 C/ BUT APPARENTLY QUITE SHALLOW AS INDICATED BY 12Z ASCENTS ... LEADING TO INVERTED-VEE TYPE PROFILES OVER SE EUROPE. VIENNA 12Z ASCENT INDICATES NOT AS DEEP A BOUNDARY LAYER WHICH HAS ALLOWED FOR MORE AMPLE MOISTURE TO BE TRAPPED IN THE LOWEST 100 HPA. THIS AIRMASS IS EXPECTED TO SPREAD WEST INTO S GERMANY AND FRANCE AT THE SRN FLANK OF THE BUILDING CENTRAL EUROPEAN SFC HIGH.

EXPECT REMNANTS OF OVERNIGHT'S CONVECTION TO LINGER OVER MUCH OF THE N BALKAN STATES...AUSTRIA...CHECH REPUBLIC AND S GERMANY DURING THE FIRST HALF OF THE DAY. UNIMPEDED INSOLATION SHOULD BE REALIZED OVER MUCH OF THE AREA TOWARDS MID DAY ... AND CINH SHOULD BE SUFFICIENTLY WEAKENED TO ALLOW MOUNTAINS/HILLS TO INITIATE TSTMS SUCH AS THE ALPS ... THE DINARIC ALPS AND OTHER OROGRAPHIC FEATURES.

GIVEN WEAK CAPPING ... WEAK SHEAR AND WEAK UPPER SUPPORT ... INDIVIDUALL CELLS SHOULD BE QUITE SHORT LIVED. HOWEVER ... TSTMS MAY CONGEAL INTO SEVERAL LARGER CLUSTERS TOWARDS LATE AFTERNOON. THOUGH PRIMARY THREAT WILL LIKELY BE LOCAL FLASH FLOODING ... STORMS IN INVERTED-VEE ENVIRONMENT WILL POSE THE THREAT OF A FEW STRONG/DAMAGING WIND GUSTS ALONG WITH SMALL HAIL. LOW PROBABILITIES FOR BRIEF MESOCLONES EXIST IF CELLS INTERACT FAVORABLY WITH ONE OF THE OUTFLOW BOUNDARIES EITHER LAID OUT BY OVENIGHT'S OR BY AFTERNOON CONVECTION ... BUT A SLIGHT RISK IS NOT NECESSARY. AS LOW-LEVEL WAA STRENGTHENS OVER FRANCE ... S BENELUX AND CENTRAL GERMANY DURING THE NIGHT ... A FEW ELEVATED TSTMS COULD DEVELOP LATE TUESDAY NIGHT/EARLY WEDNESDAY MORNING. SEVERE THREAT SHOULD BE MINIMAL WITH THIS ACTIVITY.

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